Conversion of sulfur-containing hydrocarbons



Aug. l2, 1969 A. c. HANSEN, JR

CONVERSION OF SULFUR-CONTAINING HYDROCARBONS Filed Sept. 6, 1966 Hansen, Jl:

Q. Q4-arf Andrew MM PWM A TTOR/VEXS United States Patent Oil-"ice 3,461,062 Patented Aug. 12, 1969 U.S. Cl. 208-89 9 Claims ABSTRACT F THE DISCLOSURE A combination hydrorening and hydrocarbon conversion process wherein a portion of the total conversion product is recycled to combine with the charge-stock prior to hydrorelining. The duty on the hydrorening heater is reduced while an increase in both quantity and quality of desirable conversion product is obtained.

The present invention relates to the conversion of hydrocarbons and mixtures of hydrocarbons which are considered contaminated as a result of the inclusion of sulfurous compounds. In particular, the invention described herein is applicable to the conversion of hydrcarbons boiling within the normal gasoline range, although kerosenes, heavy naphthas, light gas cils, or mixtures thereof with gasolines may be used as charge stocks. More specifically, the invention is directed toward the production of high octane gasoline from sulfur-containing gasoline boiling range hydrocarbons, through a combination of interrelated steps involving principally hydroreiining and catalytic reforming.

Recent developments Within the petroleum industry have resulted in a catalytic composite capable of converting low-quality hydrocarbons and mixtures of lowquality hydrocarbons into a high-quality, more valuable product, and especially into motor fuels possessing excellent anti-knock properties. This catalyst, comprising a Group VH1 noble metal, and especially platinum and/or palladium, promotes the desirable reforming of mixtures of hydrocarbons by elfecting a balance among, as principal reactions, the dehydrogenation of naphthenes into aromatics, the dehydrocyclizatoin of paraflins to aromatics, the isomerization of straight chain parafiins to more highly branched parafns, and the hydrocracking of higher molecular weight parailins into lower boiling normally liquid hydrocarbons. Furthermore, these noble metal catalysts can be tailored to eiect specific reactions on substantially pure hydrocarbons at particularly selected operating conditions. Thus, this type of catalyst has found wide-spread use in the isomerization of cycloparatiins, paraii'lns having 4-7 carbon atoms per molecule, and in the hydrodealkylation of alkylaromatics to produce aromatic hydrocarbons.

When effecting the conversion of hydrocarbons, or mixtures of hydrocarbons, contaminated by the inclusion of sulfurous compounds, undesirable poisoning of the catalytic components occurs. Additionally, the presence of nitrogenous compounds is detrimental to many of the foregoing reactions, and, furthermore, with respect to catalytic reformation, or isomerization, the hydrocarbon charge stock should be substantially free from olelinic material. This is well known by those having expertise in petroleum refining technology, and the majority of integrated reneries have facilities specifically designed to remove such contaminating influences in order to prepare a given charge stock for further processing. Prominent among the many available schemes for the removal of sulfurous and nitrogenous compounds, is catalytic hydrorening. Through the use of a catalytic composite, generally comprising two or more metals from Group VI and the iron-group, the detrimental material is converted into ammonia, hydrogen sulfide, the liquid product eluent is generally immediately utilized in the subsequent conversion zone, regardless of the precise function of the latter.

An object of the present invention is to provide a combination process for effecting the conversion of sulfurcontaining hydrocarbons.

A principal object resides in the production of high.

octane gasoline by a more economical combination of hydrorelining and catalytic reforming.

Another object is to integrate a hydrocarbon conversion process With a hydrocarbon treating process in la manner which alfords unusual economic advantages.

One embodiment of the present invention, which attains the above-described objectives, involves a combination process for the conversion of a sulfur-containing hydrocarbon charge stock which comprises the steps of: (a) contacting said charge stock and hydrogen with a hydrorening catalyst in a hydrorelining zone at conditions selected to convert sulfurous compounds to hydrogen sulfide and hydrocarbons; (b) removing hydrogen sulide from the resulting hydrorelined effluent; (c) introducing at least a portion of the remainder of said hydrorelinde euent into a conversion zone containing a hydrocarbon conversion catalyst, and maintained at hydrocarbon conversion conditions; and, (d) recycling at least a portion of the total resulting conversion zone etliuent to combine with said hydrocarbon charge stock prior to contacting the latter in said hydroreining zone, and separating the remainder of said conversion zone efuent to provide a hydrogen-rich gaseous phase and a normally liquid hydrocarbon product.

In a specific embodiment, directed toward a particular conversion process, the present invention relates to a combination process for catalytically reforming a sulfur-containing hydrocarbon charge stock which comprises the steps of: (a) contacting said charge stock and hydrogen with a hydrorening catalyst in a hydrorelining zone at conditions selected to convert sulfurous compounds into hydrogen sulfide and hydrocarbons; (b) removing hydrogen sulfide from the resulting hydrorelined effluent; (C) introducing at least a portion of the remainder of said hydrorened eiiiuent into a catalytic reforming reaction zone maintained at reforming conditions, and containing a Group VIII noble metal catalyst; (d) recycling the total resulting reformed effluent, in an amount of from about 1.0% to about 10.0% by volume, to combine with said charge stock and prior to contact in said hydroreiining zone; (e) separating the remainder lof said reformed effluent to provide a hydrogen-rich gaseous phase, recycling said gaseous phase to combine with the charge to said reforming zone, and recovering a normally liquid reformed hydrocarbon product.

The process of the present invention may be further characterized through the operating conditions imposed upon the reaction zones. For the most part, these are welldefined in the literature, and, therefore, form no essential ingredient of my invention; the conditions are herein presented for the sake of completion and clarity. A preferred technique for treating the hydrocarbon charge stock, to remove sulfur, nitrogen and to hydrogenate oleiins, makes use of a fixed-bed catalytic reaction zone containing a hydrogenation catalyst having at least one metallic component from Group VI and the iron-group. Thus, the active components are selected from the group of iron, cobalt, nickel, tungsten, molybdenum, chromium, compounds thereof and mixtures of two or more. Operating conditions include a pressure above about 250 p.s.i.g., with an upper limit of about 2000 p.s.i.g., a temperature, at the inlet of the catalyst bed of 300 F. to about 800 F., which temperature is generally controlled to maintain the outlet temperature at a level below about 850 F., a liquid hourly space velocity of from 1.0 to about 20.0; and,

as an essential element of my inventive concept, from about 1.0% to about 10.0% by volume of the total efuent emanating from the subsequent conversion zone. Under these conditions, sulfurous and nitrogenous compounds are converted into hydrocarbons, ammonia and hydrogen sull-ide, and olefins are substantially completely hydrogenated to parans.

The operating conditions imposed upon the subsequent conversion zone will, of course, be dependent upon the type of reaction being effected therein-likewise the precise character of the catalytic composite is dependent upon the character of the process. As an example, considering the Well-known catalytic reforming process, using a fixed-bed catalyst system comprising alumina, halogen and a component from Group VIII noble metals and compounds thereof, the operating conditions include a temperature within the range of 300 F. to about 1000 F., a pressure of about 250 p.s.i.g. to about 2000 p.s.i.g., a liquid hourly space velocity of 1.0 to 20.0, and a hydrogen to hydrocarbon oil mol ratio of about 4:1 to 20: 1.

Another petroleum refining process to which the present invention is uniquely applicable, is a process for the dealkylation of alkylaromatic hydrocarbons. fIn such a process, hydrodealkylation conditions include a temperature in the range of 1000 F. to about 1500" F., a pressure of from about 400 to about 1100 p.s.i.g., a liquid hourly space velocity of from about 1.0 to about 20.0. Other hydrocarbon conversion processes, the charge stocks to which contain sulfur, may be benefited through the use of this invention, and such other processes will be recognized by those having the requisite skill in the art.

In order to further illustrate the method by which the present combination process is effected, exemplified by a catalytic reforming operation, reference is made to the accompanying figure. Miscellaneous equipment including valves, compressors, pumps, heat-exchangers, reboilers, controllers, etc., have been reduced in number or eliminated as not being essential to an understanding of the inventive concept. The use of such items will become apparent from the following description.

Referring now to the drawing, illustrating a combination process in Which a sulfur-containing, gasoline boiling range naphtha is to be converted into a high octane motor fuel, reactor 4 is a fixed-bed catalytic unit containing a cobalt molybdenum hydrogenation/desulfurization catalyst, and is maintained under a pressure of about 375 p.s.i.g., the catalyst bed inlet temperature being controlled at about 650 F. and the charge stock, entering the process via line 1 is at a rate resulting in a liquid hourly space velocity of about 8.0. The charge stock is a 50/50 blend of Heide and Arabian naphthas, having an initial boiling point of about 210 F. and an end boiling point of about 355 F. ln addition to nitrogen and a substantial quantity of unsaturated hydrocarbons, the heavy naphtha contains 0.031% by weight of sulfur, and has an octane rating of about 65 F-l Clear.

The charge stock enters the process through line 1 into heater 2, wherein the temperature of the charge is raised to a level such that the catalyst bed inlet temperature in reactor 4 is 650 F. The duty (Btu/hr.) on heater 4 is dependent upon the heat content of the reformed product eluent in line 18 which is admixed with heater 2 etlluent in line 3. The source of the material in line 1S is hereinafter set forth. The mixture continues through line 3 into reactor 4, wherein the sulfurous compounds are converted into hydrogen suliide and hydrocarbons, and olefins are substantially, completely saturated.

The hydroreiined eluent, leaving reactor 4 via line 5 is cooled to a temperature of about 100 F. in cooler 6 and continues through line 7 into separator t5. Separator 8 operates at substantially the same pressure as reactor 4- obviously somewhat lower as a result of friction loss through the system. A gaseous phase is withdrawn from line 9 containing pressure control valve 10, and is utilized to maintain pressure on the hydrorefining reactor system. Although not indicated in the drawing, when reactor -17 operates at a higher pressure than reactor 4, and all the excess separator 23 gas is recirculated to the hydrorening zone instead of being vented through line 25, control valve 10 will be activated by the varying pressure in reactor 17. That is, reactor 4 and separator S are said to float on reactor 17 pressure.

A mixed-phase stream is withdrawn from separator 8 via line 11, and is introduced into fractionator 12. The function of this vessel is to remove the hydrogen sulfide, from the normally liquid product, through line 13. Although shown as a fractionator, it is understood that vessel 12 may take any form which is applicable to producing a substantially sulfur-free normally liquid product. Also, vessel 12 may be combined with other fractionators, or even modified, to produce selective concentrates of lower molecular weight hydrocarbonsie a propane through pentane fraction. Thus, many such hydrorening units of this nature make use of a gas-stripping column, employing hydrogen as the stripping medium, in combination with a series of fractionators resulting in a sulfurfree, hexane-plus liquid product effluent in line 14.

After being admixed with a hydrogen-rich recycle gas stream from line 24, raised to the desired pressure by compressive means not shown, the liquid hydrorefned etiiuent continues through line 14 into heater 15, wherein the temperature is raised to a level of about 1000 F. The heated material continues through line '16 into reforming reactor 17, containing a catalyst of alumina, platinum and combined chloride. The rate of ow into reactor 17 is such that the liquid hourly space velocity is about 1.5, the pressure -being maintained at about 450 p.s.i.g. The reformed product effluent is removed from reactor 17, at a temperature of about 960 F., through line 1S. A portion of this stream, about 3.5 mol percent, continues through line 18 to combine with the heated charge from heater 2 in line 3. The remainder of the reformed product effluent is diverted through line 20 into cooler 21, continuing through line 22 (at a temperature of about F.) into separator 23.

Separator 23 serves to provide a hydrogen-rich recycle gas stream in line 24, which is raised to the 450 p.s.i.g. operating pressure by compressive means not shown, and combined with the reforming unit charge in line 14. The normally liquid reformed product effluent is Withdrawn from separator 23 through line 27, and transferred to suitable stabilization means for the purpose of recovering the desired gasoline boiling range product. Such stabilization means usually include a depropanizer and a debutanizer from which is recovered a pentane-plus (up t0 about 400 F.) reformed gasoline. Pressure control is maintained on reactor 17 by venting excess gas through line 25 containing valve 26.

Before illustrating my invention by Way of a more specic example, the several immediately recognized advantages Will be pointed out with reference to the drawing. One of the principal advantages resides in the signicantly decreased duty (Btu/hr.) imposed upon heater 2 in order to raise the temperature of the charge stock to the catalyst bed inlet temperature. The 3.5 mol percent of total reforming zone effluent continuing through line 18 to combine with the charge to reactor 4, at a temperature of say 950 F., supplies about 2.7 million B.t.u./hr. to the hydroreiining charge preheat, or about 60% of the normal duty placed upon heater 2 in the absence of this recycle. This permits a much lower transfer temperature on the heater, with consequent reduction in the tube quality requirements. This further avoids the expense of cooling all the hydrogen to reforming separator 23, and the subsequent rehearing of that portion recycled to the hydrorelining zone. That the recycled reformed product, at 950 F., contains about 5.0% to about 15.0% by volume of pentanes and heavier hydrocarbons in the vapor state, is of no consequence, since these will pass through the hydroreiining and reforming zones unchanged, and simply function as an added diluent with respect to the reforming zone. Although the additional load on the reforming unit would require some additional heating, no cooling would be necessary. Furthermore, the material as a diluent will not require additional hydrogen recycle through line 24. It is noteworthy too, since the recycled product stream, when taken in conjunction with the usual hydroretined eluent, improves the octane rating of the ultimate charge to the reforming zone, the severity requirement for reforming to a given quality will be reduced. That is, in order to produce the same quality product, the temperature may be lowered or the liquid hourly space velocity increased. Conversely, operating with reformed product recycle will result in increased product quality at the same severity requirements without product recycle.

Depending, of course, on the precise reforming operating conditions, the vaporous product recycle in line 18 will contain many times as many mols of hydrogen than of hydrocarbon vapors. The higher the design severity and gas recycle to hydrocarbon mol ratio in the reforming unit, the smaller will be the amount of heavy hydrocarbons (pentanes-plus) in the product recycle and a larger amount of heat will be supplied for the fresh charge to the hydrorefining unit. In fact, in some instances, the need for heater 2 may be eliminated. With some of the heavier sulfur-containing stocks, it may be desirable to divert a small portion of the product recycle to combine with the fresh charge stock prior to heater 2. This is indicated in the drawing as taking place via line 19. Such necessity does not occur too often, and in the majority of situations, all the product recycle will be diverted downstream of heater 2.

Other attendant advantages include a lessening of corrosion with respect to heater 2, as a result of the lower required outlet temperature. Less corrosion in turn leads to less iron sulfide migration to the hydroreiining catalyst bed with accompanying abatement of catalyst fouling. Also, since the same quality product can be obtained at a lower severity, lesser quantities of the charge to the reforming unit will be converted into lighter normally gaseous hydrocarbons, thereby increasing the quantity of normally liquid hydrocarbons having the desired quality.

The following specific examples are presented for the purpose of further illustrating the present invention and the benefits to be afforded through the utilization thereof. It is not intended to restrict the invention to the charge stock, operating conditions, rates, etc., beyond the scope and spirit of the appended claims.

EXAMPLE I The charge stock is the heavy naphtha mixture previously described with reference to the drawing. As previously stated, it is desired to produce a reformed gasoline product having an octane rating of 95 F-l Clear. Without recycle of a portion of the total reforming reaction zone eiuent, at a fresh feed charge rate of 4000 b./d., the hydroretining operating conditions are a liquid hourly space velocity of 8.0, a pressure of 375 p.s.i.g., a catalyst bed inlet temperature of 650 F., and a gaseous phase recycle rate (from the subsequent catalytic reforming product separator) of about 380 s.c.f./bbl. (1.52 million s.c.f./d.), or a hydrogen concentration of about 300 s.c.f./ bbl. of fresh charge stock.

The combined feed to the hydrorefining zone is preheated via heat-exchange with the reaction product eiliuent to a temperature of about 540 F., and is introduced into the charge heater wherein the temperature is increased to a level of about 650 F. The heater duty, in millions of Btu/hr., is 4.52. Following the use of the hydrorefined effluent to preheat the fresh charge stock, the total eilluent is cooled to about 90 F., and passes into a products separator. A gaseous phase, having a molecular Weight of 4.7 and containing about 28.0% of the hydrogen sulfide resulting from the hydroreining reactions, is vented from the separator. A liquid phase is introduced into a stripping column in which the remainder of the hydrogen sulfide is removed, and the reforming charge, in an amount of 4000 b./d. of hexane-plus only, is withdrawn as a bottoms stream.

The reforming charge is combined with a hydrogenrich recycle gas stream (hydrogen to hydrocarbon mol ratio of 10:1), and the mixture, following heat-exchange with the reforming zone effluent, passes into a heater wherein the stream is raised to a temperature of 1000 F.

The heater duty (total) imposed on the reforming charge heater, in millions of B.t.u./hr., is 29.3. The reforming reactor is under an imposed pressure of 550 p.s.i.g.; `and the charge rate is such that the liquid hourly space velocity is 1.5. The total effluent from the reforming zone, at a temperature approximating 960 F., after being utilized to preheat the reforming charge stream, is cooled to F. and introduced into a products separator. The normally liquid product effluent, in an amount of 3871 b./d., is passed into `a fractionator for stabilization to the desired product. The gaseous phase, 46.0 millions s.c.f./b., is in part recycled to combine with the reforming unit charge (42.7 millions s.c.f./d.), in part vented for pressure control (1.8 millions s.c.f./d.) and in part recycled to the hydrorefining zone (1.52 millions s.c.f./d.).

The stabilization section is operated to produce a substantially debutanized pentane-plus gasoline product, in an amount of 3020 b./d., having an octane rating of 95.0 F-l Clear. An analysis of the product is presented in the following Table l: v

Table I Component: Mol percent Iso-butane 0.1 N-butane 0.9 Iso-pentane 8.5 N-pentane 5.9 Hexane-plus 84.6

EXAMPLE II In order to illustrate the method and advantages of the present invention, a single change is instituted in the flow as described in Example I. This change is to the eifect that a portion of the hot, total reformed product effluent is diverted, without intermediate cooling of `any kind, to combine with the hydrorening charge stock after the latter has been preheated. The hydrorefining zone is maintained at the same operating conditions as stated in Example I; the temperature is 650 F., the pressure is 375 p.s.i.g. and the liquid hourly space velocity is 8.0.

The fresh charge rate to the hydrorefining charge heater is 4000 b./d. of hexane-plus material only; that is, there is no admixture of the charge with hydrogen recycle (from the reformed product separator) upstream of the heater. After preheat via heat-exchange with reaction zone effluent, the charge enters the heater at about 540 F., wherein the temperature is raised to a level of about 600 F. The heater duty, in millions of B.t.u./hr. is 1.82. The thus-heated charge is admixed with about 3.5 mol percent of the total reformed product eluent, at a temperature of 950 F., (supplying therefore, 2.7 10i Btu/hr.) obtained as hereinafter set forth, and the resulting mixture enters the hydrorening zone at a temperature of 650 F., containing about 300 s.c.f. of hydrogen per barrel of charge. This hot reformed product effluent has the component composition indicated in the following Table II:

At a rate of 3.5 mol percent, 186 mols/hr. are diverted to the preheated hydroretining charge. In terms of added hexane-plus hydrocarbons to the system, this amounts to approximately 100 b./d.

After cooling to a temperature of about 80 F., the hydrorefined effluent is passed into a products separator, from which a gaseous phase containing about 28.0% of the hydrogen sulfide, is vented. A principally normally liquid phase is stripped of the remainder of the hydrogen sulfide, and the hydrogen sulfide-free hydrocarbons are subjected to fractionation to provide a depentanized hexane-plus material as the reforming charge. 'I'his material, in an amount of about 4100 b./d., is combined with a hydrogen-rich gas stream in a hydrogen/hydrocarbon mol ratio of 10:1. The mixture, after heat-exchange with reformed product efiiuent, passes into a heater wherein the stream is raised to a level of 1000 F. The heater duty (total) imposed upon the reforming charge heater, in millions of B.t.u./hr., is 30.0.

As in Example I, the reforming reaction zone is maintained under an imposed pressure of 550 p.s.i.g., and the charge rate is such that the liquid hourly space velocity is 1.5. The total reformed product eiuent exists at a temperature of 960 F.; 3.5 mol percent of this stream is diverted directly, without intermediate cooling of .any kind, to combine with the preheated fresh charge, supplying thereto 2.7)(106 B.tu/hr., and raising the temperature thereof from about 600 F. to about 650 F., being the inlet temperature to the hydrorefining zone. After being used to preheat the charge to the reforming zone, the remainder of the reformed effluent is cooled to 90 F., and passes into a products separator. The normally liquid product effluent, in an amount of about 3880 b./ d. passes into a fractionator for stabilization to the desired product. The gaseous phase (44.4 millions s.c.f./d.) is in part recycled to combine with the charge to the reforming zone, 42.7 millions s.c.f./d., and in part Vented for pressure control, 1.7 millions s.c.f./ d.

The 3880 b./d. of liquid from the reforming products separator is stabilized to produce a substantially debutanized, pentane-plus product, in an amount of about 3030 b./d., and having an octane rating of 97.5 F-l Clear. An analysis of this product is presented in the following Table III:

Table III Component: Mol percent Iso-butane 0.3 N-butane 0.7 Iso-pentane 9.5 N-pentane 4.9 Hexane-plus 84.6

As stated in Example I, an object of this operation is to recover propane-rich .and butane-rich material from the various streams vented from the process. In this illustration, the propane is recovered in an amount of about 290 b./d., and butane in an amount of about 397 b./d. From the 4000 b./d. of fresh charge, 3717 b./ d. of desired product is recovered.

A comparison of the results from the two operations described in the foregoing examples, reveals the advantages of the hot product recycle to the hydrorefining zone. The duty imposed upon the hydrorefiuiug charge heater has been decreased from 4.52 106 B.t.u./hr. to 1.82)(106 B.t.u./hr., a savings of 2.7 106 B.t.u./hr. The fact that additional mols of hexane-plus must therefore pa-ss through the reforming charge heater results in an increase in heater duty of 0.7)(106 B.t.u./hr. The overall benefit, in terms of 106 B.t.u/hr., is 2.0, or about 6.1%. Important, however, is the fact that the duty on the hydrorefining heater has been decreased about 60.0%. Furthermore, since the octane rating of the charge to the reforming zone has been improved, the octane rating of the final desired product is increased, notwithstanding no change in the operating conditions of the reforming unit. A consequence of this resides in the fact that the severity of the reformer can be reduced While producing the same quality product, and a reduction in severity leads to a greater yield of product, based upon fresh charge.

I claim as my invention:

1. In a process for the conversion of a sulfur-containing hydrocarbon charge stock which comprises the steps of:

(a) contacting said charge stock and hydrogen with a hydrorening catalyst in a hydrorefining zone at conditions selected to convert sulfurous compounds to hydrogen sulfide and hydrocarbons;

(b) removing hydrogen sulfide from the resulting hydrorefined eluent;

(c) introducing at least a portion of the remainder of said hydrorefined eiuent into a conversion zone containing a hydrocarbon conversion catalyst, and maintained at hydrocarbon conversion conditions; and,

(d) separating the conversion zone effluent to provide a hydrogen-rich gaseous phase and a normally liquid hydrocarbon product, the improvement therein which comprises recycling from about 1.0% to about 10.0% by volume of the total resulting conversion zone effluent to combine with said hydrocarbon charge stock prior to contacting the latter in said hydrorefining zone, said recycle, at the time of said combining with the charge stock, being characterized by a temperature approximating the conversion zone temperature.

2. The process of claim 1 further characterized in that said hydrocarbon charge stock comprises an alkylaromatic hydrocarbon, and said conversion conditions are selected to dealkylate said alkylaromatic hydrocarbon.

3. A process for catalytically reforming a sulfur-containing hydrocarbon charge stock which comprises the steps of:

(a) contacting said charge stock and hydrogen with a hydrorefining catalyst in a hydrorefining zone at conditions selected to convert sulfurous compounds into hydrogen sulfide and hydrocarbons;

(b) removing hydrogen sulfide from the resulting hydrorefined effluent;

(c) introducing at least a portion of the remainder of said hydrorefined effluent into a catalytic reforming reaction zone maintained at reforming conditions, and containing a Group VIII noble metal catalyst;

(d) recycling the total resulting reformed effluent, in an amount of from about 1.0% to about 10.0% by volume, to combine with said charge stock prior to contact in said hydrorening zone, said recycle, at the time of combination with said charge stock being characterized by a temperature approximating the reforming reaction zone temperature; and

(e) separating the remainder of said reforming efiiuent to provide a hydrogen-rich gaseous phase, recycling said gaseous phase to combine with the charge to said reforming zone, and recovering a normally liquid reformed hydrocarbon product.

4. The process of claim 3 further characterized in that said hydrorefining conditions include a temperature within the range of 300 F., to about 800 F., a pressure of from about to about 900 p.s.i.g. and a liquid hourly space velocity of from about 1.0 to about 20.0.

5. The process of claim 3 further characterized in that said reforming conditions include a pressure in the range of 300 to about 1000 p.s.i.g., a temperature of from about 300 F. to about l000 F. and a liquid hourly space velocity of from 1.0 to about 20.0.

6. The process of claim 3 further characterized in that said reforming zone is maintained under a greater pressure and at a higher temperature than said hydrorefning zone.

7. The process of claim 3 further characterized in that said charge stock comprises gasoline boiling range hydrocarbons.

8. The process of claim 3 further characterized in that the reformed eluent is recycled to the hydrorefining zone without intermediate cooling.

10 9. The process of claim 3 further characterized in that said Group VIII noble metal catalyst comprises platinum.

References Cited UNITED STATES PATENTS 2,889,263 6/ 1959 Hemminger et al. 208-89 DELBERT E. GANTZ, Primary Examiner A. RIMENS, Assistant Examiner U.S. C1. X.R. 

